TSS Transport Simulation Systems


TSS Transport Simulation Systems

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Badia H.,University of Barcelona | Argote-Cabanero J.,TSS Transport Simulation Systems | Argote-Cabanero J.,Berkeley Analytics, Inc. | Daganzo C.F.,University of California at Berkeley | Daganzo C.F.,Berkeley Analytics, Inc.
Transportation Research Part A: Policy and Practice | Year: 2017

Conventional wisdom states that transit riders are averse to transfers and that consequently bus networks should be designed to limit their number. Probably as a result of this belief, many real bus systems try to connect as many origins and destinations as possible without transfers, so they are usually composed of long, circuitous routes with redundant overlapping sections – and the resulting bus map is hard to understand. If coverage is extensive, many routes are needed. Economics then prevents an agency from populating all routes with sufficient buses to provide attractively frequent service. This low frequency and the complicated circuitous map discourage transfers, perpetuating the belief that people are averse to transferring. Not surprisingly, the percentage of bus trips that includes a transfer has been reported to be: 1.5% for Boston, 3% for New York, 13% for London, and 16% for Melbourne. The Nova Xarxa in Barcelona was designed with a different paradigm. It was designed and deployed to cover the whole city on the belief that if a bus map is easy to understand, and has direct lines with frequent service and ubiquitous transfer points then the bus system would become more appealing, people would transfer more freely and become users of the network rather than its single lines. With this design paradigm, a city can be covered with fewer lines, which can be depicted on a simple map. The lines can in turn be economically populated with sufficient buses to deliver the high frequency required to encourage transfers. Could this work? To answer this question and see whether there is truth in the beliefs underlying the new paradigm, this paper examines data from the first three deployment phases of the Nova Xarxa (from 2012 to 2015). It is found that the Nova Xarxa is already attracting more demand than the network it replaced. This attests to its appeal. Furthermore, this demand has increased disproportionately with the number of lines opened for service in each phase, revealing that some people are using the Nova Xarxa as a network. The paper further shows that this growth is underpinned by transfers - at the end of 2015, the percentage of trips that involved a transfer was approximately 26%, and it reached a maximum of 57% for line V7. These numbers should increase considerably (to 44% and 66%, respectively) once the Nova Xarxa is completed in 2018 and passengers have even more opportunities for transferring. The numbers disprove the conventional wisdom. They strongly suggest that transit providers can attract more demand by providing transfer-friendly networks that can be used as such and not as an inefficient aggregation of individual lines. © 2017 Elsevier Ltd

Antoniou C.,National Technical University of Athens | Barcelo J.,University of Barcelona | Breen M.,TSS Transport Simulation Systems | Bullejos M.,University of Barcelona | And 12 more authors.
Transportation Research Part C: Emerging Technologies | Year: 2015

Estimation/updating of Origin-Destination (OD) flows and other traffic state parameters is a classical, widely adopted procedure in transport engineering, both in off-line and in on-line contexts. Notwithstanding numerous approaches proposed in the literature, there is still room for considerable improvements, also leveraging the unprecedented opportunity offered by information and communication technologies and big data. A key issue relates to the unobservability of OD flows in real networks - except from closed highway systems - thus leading to inherent difficulties in measuring performance of OD flows estimation/updating methods and algorithms. Starting from these premises, the paper proposes a common evaluation and benchmarking framework, providing a synthetic test bed, which enables implementation and comparison of OD estimation/updating algorithms and methodologies under "standardized" conditions. The framework, implemented in a platform available to interested parties upon request, has been flexibly designed and allows comparing a variety of approaches under various settings and conditions. Specifically, the structure and the key features of the framework are presented, along with a detailed experimental design for the application of different dynamic OD flow estimation algorithms. By way of example, applications to both off-line/planning and on-line algorithms are presented, together with a demonstration of the extensibility of the presented framework to accommodate additional data sources. © 2015 Elsevier Ltd.

Ciuffo B.,Institute for the Environment and Sustainability | Casas J.,TSS Transport Simulation Systems | Montanino M.,University of Naples Federico II | Perarnau J.,TSS Transport Simulation Systems | Punzo V.,European Commission - Joint Research Center Ispra
Transportation Research Record | Year: 2013

This study adopted a metamodel-based technique for model sensitivity analysis and applied it to the AIMSUN mesoscopic model. The application of sensitivity analysis is crucial for the true comprehension and correct use of the traffic simulation model, although the main obstacle to an extensive use of the most sophisticated techniques is the high number of model runs such techniques usually require. For this reason, the possibility of performing a sensitivity analysis was tested not on a model but on its metamodel approximation. Important issues concerning metamodel estimation were investigated and commented on in the specific application to the AIMSUN model. Among these issues are the importance of selecting a proper sampling strategy based on low-discrepancy random number sequences and the importance of selecting a class of metamodels able to reproduce the inputs-outputs relationship in a robust and reliable way. Sobol sequences and Gaussian process metamodels were recognized as the appropriate choices. The proposed methodology was assessed by comparing the results of the application of variance-based sensitivity analysis techniques with the simulation model and with a metamodel estimated with 512 model runs for a variety of traffic scenarios and model outputs. Results confirmed the power of the proposed methodology and also made a more extensive application of sensitivity analysis techniques available for complex traffic simulation models.

Vilaro J.C.,TSS Transport Simulation Systems | Vilaro J.C.,University of Vic | Torday A.,TSS Transport Simulation Systems | Gerodimos A.,TSS Transport Simulation Systems
IEEE Intelligent Transportation Systems Magazine | Year: 2010

The evaluation of advanced Intelligent Transportation Systems, and particularly those which involve real-time traffic management, requires a network-wide assessment of their impact as opposed to an isolated analysis of key intersections. To support such assessments, an integrated simulation environment that allows the use of different modeling levels (e.g., macro-meso-micro) offers undeniable advantages. One of the advantages is that traffic assignment results produced by any type of network loading modeling can be stored and reused for another simulation run. But even in an integrated environment with separate models, deciding between microscopic or mesoscopic was until recently a necessary and difficult choice. On the one hand, microscopic traffic simulation models emulate the dynamics of individual vehicles in a detailed network representation based on car-following, lane changing, and gap acceptance models. They also account explicitly for traffic control. As such, they are very appropriate for operational analysis due to the detail of information provided by the simulator. However, they have a significant calibration and computational cost. On the other hand, mesoscopic models combine simplified flow dynamics with explicit treatment of interrupted flows at intersections and allow modeling of large networks with high computational efficiency. However, the loss of realism implied by a mesoscopic model makes it necessary to emulate detailed outputs; for instance, de-tector measurements or instantaneous emissions. Some outputs, such as the number of start-stops or the exact location of con-gestion within a section elude even the most detailed mesoscopic simulators. This analysis gives rise to the need to combine meso and micro approaches into new concurrent hybrid traffic simulators where very large-scale networks are modeled mesoscopically and areas of complex interactions benefit from the finer detail of microscopic simulation. Combining an event-based mesoscopic model with a more detailed, time-sliced microsimulator raises consistency problems within the network rep-resentation and the meso-micro-meso transitions. This paper discusses these problems, proposes solutions and illustrates how they work in practice. © 2010 IEEE.

Tss Transport Simulation; Systems | Date: 2010-01-12

Computer programs for analyzing and simulating mobility of people and goods and multi-modal surface traffic, namely, private vehicles, public transport, logistics fleet vehicles, emergency vehicles, motorcycles as well as pedestrians, bicycles and other non motorized vehicles.

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